Synchronizer



July 9, 1940., J. E. DIAMOND 2,297,446

SYNCHRONIZER Original Filed Oct. l0, 1953 5 Sheets-Sheet 2 July 9, i940.J, E. DIAMOND SYNGHRONIZER Original Filed Oct. 10, 1933 umm 5Sheets-Sheet 3 @2a. @Zz

July 9, 1940.

J. E. DIAMOND 21,207,446

sYNcnBoNIzER Original Fil'e d Oct. l0( 1,933 5 Sheets-Sheet 4 Illini;If; f5 mm m lNvENToR Jmefz'awzwzd BY Mw ATTORNEYS July 9, 1940. J. E.DIAMOND 5 Sheets-Sheet 5 SYNCHRONIZER Original Filed Oct. l0,` 1933 ig3a 0 Z 7 m w mm fd Patented July 9, 1940 eine Application October 10,1933, Serial No. 692,932 Renewed March 27, 1937 22 Claims.

As is well known in the art, in military planes, especially in thecombat type, in which machine guns are fixed immovably with respect tothe aircraft, it is usually desirable to mount the guns on,

' or, in the fuselage. This mounting almost invariably brings the lineof fire of guns so mounted within the periphery described by thepropeller, that it is within what is known as the propeller disk area,since combat planes are at the present time, without exception, of thetractor type, which for the benefit of those not familiar with aircraftstructures, is the one where the propeller is, or the propellers are, inadvance of the leading edge or edges of the wing or wings.

As will be appreciated, a denite relation must be established betweenthe positions of the propeller blades, of which there are always two ormore, and the time at which a machine gun is permitted to re. In otherwords the firing of the machine gun must be synchronized with respect tothe movement of the propeller.V Many avenues have been followed inattempting to reach a satisfactory solution of this problem. Manymethods of attaining synchronization have i5 been tried. Among thosehave been ones based upon the laws of hydraulics. Other attempts havebeen made to utilize electric apparatus, but each has discloseddrawbacks sufficiently weighty in the light of experience to date toshow the 3V wisdom of using a synchronizer having as its principle, theestablishment of a direct mechanical relationship between the propellerand the machine gun. In present practice this is effected by means ofgearing, the propeller shaft being at :"5 one end of the train and somemeans of power take-off at the other. This train usually terminates in aform which, ultimately, either directly or indirectly should be able, atwill, to convert rotary into reciprocating motion. The reciprocat- 4 ingelement may be, and is usually termed an impulse motor, and it, in turn,by means of a flexible cable attached thereto, the reciprocation ofwhich is a function thereof, controls the firing pin of a machine gun orother similar mechanism.

This flexible cable, hereafter termed the irnpulse cable attached to thering pin, which latter is always under sufficient spring-loading to firea cartridge, as the name implies, may be flexed,

within limits, to couple the firing pin of the 5U machine gun to theimpulse motor, a component of the synchronizing device itself. Thislimit of flexure is, however, a very definite consideration in devisingsuccessful installations. It must be borne in mind that an enginelocation is very se precisely fixed with respect to a plane structure,

and while on the other hand, there is Some latitude as to the exactlocation of a machine gun or pair of machine guns with respect to thesame structure, this latitude is decidedly narrow. It therefore becomesnecessary with the scope of possibilities narrowed down by thelimitations imposed by the structure design of the airplane, andlimitations imposed by the means of attachment of engine to gun, toconform the direction of reciprocation of the synchronizer impulse motorto meet these recited conditions. It is of course feasible to convertrotary into reciprocating motion at an angle, and precisely this must bedone in many installations.

The requirement introduced by the limitations imposed in the use of someexible means of connection such as that earlier described also entersinto the problem in another respect. The trigger control mechanism issimilarly based on the employment of some flexible means of attachmentbetween the cock-pit (usually the trigger or triggers are on the controlstick) and the trigger pin or pins that release or arrest at will thefunctioning of the synchronizer or synchronizers, and consequentlyfunctioning of the gun or guns. As a result of such additionallimitation springing from the use of a flexible mechanism, there hasbeen hitherto not much latitude allowed in the choice of location of thetrigger pin with respect to the rest of the synchronizer, bearing inmind 3 the fact that the angularity between control stick and triggerpins must be held within certain limits. The significance of this isthat while by a more or less involved or complicated and weightymechanism solutions are offered to the problem of proper take-off,directionally, for the impulse motor, that is, the prime-mover,operating the firing pin of the machine gun, the relation,directionally, of the trigger pin controlling the operation of theimpulse motor-with respect to the airplane structure--will not be thesame with any two different types of aircraft. The triggerpin aspect,axially, may happen to be ideal for one type of combat ship, but theimposed angularity in the flexible connection between cock-pit andsynchronizer, in another type of fighter may, from a mechanicalstandpoint, be highly undesirable, even if possible, that is, with theseltsame synchronizer, forcing a redesign of portions of the latter tomeet the new condition.

It may be well to discuss the present practice in placing propeller andmachine gun into synchrony. With practically all previous synchronizersthe relationship between propeller and machine gun is a function of theposition of the gun synchronizer drive shaft, a detail of the engineassembly, and some driven member of synchronizer proper. Ordinarily theformer shaft terminates with some positive form of drive connection,splines for example. A mating gear may be assembled at this point. Thiswill mesh with a gear which is one of a train of gears the synchroniserproper. The procedure is to correctly place the former gear on the gunVsynchronizer drive shaft splining, a matter of experience and judgment,and then to mount the synchronizer meshing the gear to be driven also inapproximately the correct setting of the latter. The synchroniser beingin place, the synchronizer impulse motor is attached to the machine gunmechanism by means of the nexible cable herebefore mentioned.Observation is made the propeller is turned by hand as to the point offire, and the position of the propeller. If not correct, thesynchroniser must be removed, the relationship of the driving shaft tothe driven member changed.

It will be observed this is a trial-and-error method, which in view ofthe necessity of removing the synchronizer from. its position on theengine to effect the correction' desired, is time-con'- suming; and alength of time may conceivably be consumed that, in times of emergency,would prove fatal. A highly desirable condition is the elimination ofthe necessity of removalof the synchronizer proper in establishing aproper relationship between propeller and machine gun. Mechanical andmathematical considerations are factors in arriving at a quicksynchronization.

Unusual conditions of flight introduce other considerations that arepertinent. It frequently happens that with the trend toward higher andhigher engine powers, that the use of a two-blade propeller of suiicientdiameter to utilize efciently the power output of such engines` is notfeasible because of the ground clearance required, this in turn forcingthe use of landing gear of excessive height to insure proper groundclearance, introducing unwanted parasitic resistance, etc. One solutionis the use of a propeller smaller in diameter, but with a larger numberof blades, usually three. Under normal conditions, synchronization here,is not relatively much more difficult than in the case of the two-bladedpropeller in spite of the smaller track and time element allowed forfiring. However one type of military r fighting maneuver known as powerdiving introduce an entirely new element. In this maneuver therevolution of the propeller is at a vastly accelerated rate,occasionally approximately doubling. In view of this higher rate ofturning, and decreased circumferential length of clear path betweenblades, one-third less in the case of a three-blade, in comparison witha twoblade propeller, the lag in the cam follower in its follow of thecam may destroy the necessary synchrony. The advance of the cam` whenthese unusual conditions are prevailing will compensate for the lagrecited. A mechanism, making provision for automatically advancing itscam when such conditions of flight are imposed on an engine is theideal.

One of the objects of my invention is the elimination of involvedsystems of gearing or equivalent in the conversion of rotary intoreciprocating motion at angles other than at right angles as well as atright angles, thereto.

Another object of my invention is the conversion of rotary intoreciprocating motion at angles other than at right angles with the axisof the reciprocating member or members in the same plane as the axis ofthe revolving member, eliminating the staggering or offsetting otherwiseinvolved, .with the imposed consequence of increased weight-a factor ofimportance in aircraft engines or aircraft accessories.

Still another object is the reduction of the number of elements entering`into such a device, with consequent reduction in the degree ofcumulative back-lash incident to operating wear.

lvIy invention has another object: the elimination of all possibility ofwear at times that the synchronizer is not performing its function as ameter of gunfire.

Still another object is the attainment of some latitude in the vchoiceof the angularity of the angular take-olf.

Another object of my invention is to introduce an element of latitude inthe position of the trigger pin control mechanism with respect to therest of the unit, thereby facilitating installation of the flexiblecontrol assembly.

Another object in view is the elimination of the repetitious andtrial-and-error labor now necessary in establishing proper relationshipbetween propeller and gun. l

Another object of my invention is to make the vsynchronizer an entirelyself-contained unit.

Another object of my invention is to make available a synchroniserhaving a wide scope of applicability.V

Another object is to meet the requirements imposed on a synchronizerwhen called upon to function during a period in which a propeller isturning at abnormally high speed, such as during a power-dive.

Still another object is to meet in a very simple way, retaining thebenefits of my invention, the problem imposed if the power supply giventhe synchronizer must be delivered to an offset impulse motor cable,

I refer now to the drawings.

Figure 1 is a longitudinal cross-section on line i-lin Figure 2.

Figure 2 is an end Aview with one-half of the trigger vpin housingremoved.

Figure 3 is a transverse section on line 3-3 in Figure 1. i

Figure 4 is a detail showing an alternate construction.

Fgure 5 is a section on line 5 5 in Figure 1.

Figure vGis a section on line @-6 in Figure i.

Figure 7 is a diagrammatic View.

Figure 8 is a side elevation of Figure 7.

Figure 9 is a diagrammatic View.

Figure l0 is a sideV elevation of Figure 9.

Figure 11 is a fragmentary detail showing another form.

Figure 12 is a similarly fragmentary showing an alternate construction.

Figure 13 shows another fragmentary construction, being a section online l3-l3 in Figure 14:.

Figure 14 is a section on line l-ld in Figure 13.

Figure 15 isi a detail of construction pertinent to Figures 13 and 14.

Figurel is a vertical section through a modied form of the invention.

Figure 17 is a vertical section through a modified form. of camoperating mechanism.

Figure 18 is an enlarged fragmentary vertical section showing a modifiedarrangement for part of the mechanism of Fig. 17.

Figure 19 is a vertical section through still another form of operatingmechanism.

Figures 20 and 21 are fragmentary enlargements of parts of the mechanismof Fig. 19 shown in two different relative positions.

Figure 22 is a detail in vertical section of another form of operatingmechanism.

Figure 23 is an enlarged fragmentary vertical section showing a modifiedarrangement for part vof the mechanism of Fig. 22.

Figure 24 is a fragmentary enlargement of part of the mechanism shown inFig. 23.

Figure 25 is a vertical section through still another form of operatingmechanism.

Figure 26 is a vertical section in enlargement showing-the manner inwhich teeth incorporated in theV mechanism of Fig. 25 areV in mesh.

Figure 27 is a diagrammatic View.

Figure 28 is a plan View.

Figure 29 is a plan view.

Figure 30 is a View partially in section on substantially the lineBil-30 of Fig. 32.

Figure 31 is a section on line 3I-3I of Figure 30.

Figure 32 is a tcp View pertaining to Figures 30 and 31.

Figure 33 is an enlarged detail in section of a portion of Figure 31 online 3I-3I of Figure 30.

Before consi-dering the drawings in detail it may be well to recite orrestate` specifically some of the problems to be met. One is to convertrotary into reciprocating motion at various angles, with respect to theaxis of rotation, in a simple direct mechanical way, with a minimum ofparts and with a minimum of weight, and to do this in such a way as toreduce wear to an absolute minimum. In terms of the design shown inFigure 1, the problem stands to convert the rotary motion of gunsynchronizer drive shaft, I, into reciprocating motion at an obtuseangularity relative thereto and definite in magnitude at threaded hole,22, whereto is attached an impulse cable denitely controlling the fireof a machine gun some distance away.

It should not be understood that the scope of the construction beingdiscussed is to be considered as limited to angularity in the same planeas that in which falls the gun synchroniser drive shaft.

It will be obvious that if `due to the presence of some body such as anaccessory that may be so located as to interfere with .the constructionindicated above, the principle here involved lends itself well tomeeting such a situation, by permitting whatever offsetting may benecessary to clear what would otherwise be in its way, with the maximumof simplicity and the minimum of weight.

One of the forms of my invention is based on the use of two simple racks`co-acting with a pinion.

I refer now specifically to the drawings.

In Figure 1, i is one of the engine accessory drive shafts terminatingoutside the engine crankcase, and hereafter called the gun synchronizerdrive shaft, and having at its outer extremity splines 2 or similarprovision for positively driving a synohronizer unit, and means 3, inthis case the well-known screw threading to retain in place cam 4,usually elliptical in profile or contour, and locked in place by nutbecoming an integral part of the gun synchronizer drive shaft I which inthe case shown turns in an antifriction bearing housed in enginecrankcase 6. The face of cam 4 rolls against roller I which is free torotate on stud 8 which is an attached part of the cam follower andimpulse motor shaft 9 having formed on one portion a series of teeth IBand in an enlarged portion at one end an annular channel II, and at theother a threaded hole I2, or other means for attachment of an impulsecable, and likewise a keyway I3, co-acting with key I4, the shaftreciprocating in synchronizer housing I5, and trigger pin housing I6, asbearings. Rack teeth ID mesh with the gear teeth on pinion Il, bushedwith bearing I8, oscillating on pinion stud I9, retained in housing I5.The `teeth on pinion I'I mesh with rack teeth formed on a portion ofsecondary impulse motor shaft ZI in one end of which is a threaded hole22 forV attachment of an impulse cable 42;'there is also` formed in thisshaft 2i, keyway 23 co-act- .ing with key I4, hitherto mentioned.

Secondary impulse motor shaft 2l reciprocates in the bore provided forit in synchronizer housing I5. 24 and 25 are threaded portions providingmeans of attachment for the flexible tubing armoring or protecting theimpulse cable 42, which whether connected to member 9 or member 2|, isoperated from the gun to exert a pull on member 9 or 2! with the resultthat the roller may be kept in operative contact with cam 4 whiletrigger pin 28 is retracted from channel II. In other words, referringto Figure 1, the pull of cable 42 moves member 9 to the left, cam 4moves it back to the right, and the presence of pin 28 in channel IIkeeps member 9 in the Figure 1 position. 26 is a threaded hole intowhich is screwed the standard trigger pin mechanism. 21 is a distanceshim by means of which a desired relationship hereafter discussed may beestablished between the rolling face of cam 4 and roller 'I, this shimbeing interposed between synchronizer body I5 and trigger pin housingIS. 28 typiiies the trigger pin. Essentially the trigger pin mechanismis a device incorporating a spring under compression the function ofwhich is to maintain trigger pin 28 in annular channel II, except asretracted therefrom by the pulling of the trigger pro-per by the pilot,the translation of motion between cockpit and synchronizer being bymeans of the flexible trigger cable hitherto mentioned. In practice cam4 is so positioned on splines 2 that when said cam has its major axiscoincident in direction with that of the cam follower and primaryimpulse motor, the ring pin of the machine gun connected therewith bymeans of the provisions shown at I2 and 22 for attachment of the impulsecable, is restrained from firing the cartridge in the ring chamber. Thiscam setting is of course directly related to the position of thepropeller with respect to the line of fire of the machine gun controlledby the impulse motor in question. This position having been determined,shim, 2l, and of sufficient thickness to insure retraction of roller, l,from the rolling face of cam 4-a matter of several thousandths of aninch-when the end trigger pin 28 is bottomed in annular channel II. Theend of trigger pin 28 is either generously filleted or taperedr toinsure entry regardless of the fre-1 major and minor axes of cam 4. And,due to the geared relationship' between the Yformer and secondaryimpulse motor shaft 2|, the length of stroke of the latter isV a similarfunction. It will be noted that in the construction shown, the angulartake-01T is disposed directly over the engine gun synchronizer driveshaft. In practice an angularity of approximately 35 degrees has beenfound expedient. In the particular construction shown, this angularityis rigidly xed in the design of the synchronizer housing. It will beappreciated that with the construction shown, the synchronizer housing,by design, may citer any desired rigid angularity. It will further beobserved that when the cam follower and primary impulse motor shaft 9is. retracted from its functioning position, that is when the triggerpin 28 has bottomed in annular channel I I, drawing roller 'I out ofcontact with the roller face of cam t, the entire mechanism, camfollower and impulse motor shaft 9, pinion H and secondary impulse motorshaft 2| is'disengaged, inoperative and stationary, cam 4, turning idlyin space. The

importance of this. may not be too highly stressed, when it is borne inmind that the speeds involved are very high, the matter of wear in itseffect on correct synchronization, a matter of near hairline adjustment,is a vital consideration. Hitherto to attain an. approximation of thedesired angularity, recoursehas been had to a train of gears, and theconversion of rotary into reciprocating motion imposed by thenecessities of the case has been at the far end of the train, withrespect to the driving medium. The significance of this is thatregardless. of functioning, or nonfunctioning of the recirocating or camfollowing element, the gears in the train are turning continuouslyduring the operating of the engine. When it is realized that with atwo-lobe cam, one in which it may be assumed that the radii composingthe major axis are'equal, turning at engine speed, approximately 2060 R.P. M. the cam. follower is reciprocating 8000 times a minute, some ideawill be gained of the speeds invoived. When it is further appreciatedthat .the average aircraft machine gun cartridge belt normally carriesbut 120() rounds, and only one belt per gun is the normal ammunitionsupply for combat planes, replenishment requires grounding. Further, theaverage machine gun burst consists usually of approximately 25 rounds-atime element of one and one-half seconds. From the foregoing, the smallpercentages of time a gun synchronizer is called upon to function incomparison with the hours of service demanded of an engine is:impressively apparent. As previously stated, wear is an unwelcomefactor, since synchrony at the high speeds involved is so critical thatwear however slight may be just enough to destroy the synchronizationbetween gun and propeller with its understood disastrous results if thegun is red with this condition existingv while the plane is in flight.

It will be observed that in my invention, there can be absolutely nowear when the synchronizer is not performing its mission in controllingthe firing of a machine gun. It is purely an inert mechanism.

It will be noted that the operation of secondary impulse motor shaft 2|is in phase with the operation of cam follower and primary impulse motorshaft S. For a two-blade propeller this difference in phase is withoutsignificance. It may be well to point out that in no installation willimpulse be taken from both impulse motor shaft-s. Where a machine gun isto be synchronizedr to shoot thru--a three blade propeller, provisionfor such requirement is made in the design oi' cam i and the properphase relation vestablished for whichever particular impulse motor shaft9 or 2l is to be utilized.

Figure 2 which is an end view of the synchronizer shown in Figure 1, hasone-half of the triggerpinhousing, i5, removed. A series of tappedholes, 34, is revealed. These holes may be as close together as goodmachining will permit. It will be noted that orientation of trigger pinhousing, I6, is thereby made possible. A possible position is shown inthe dot and dash line. For example, if space permits the placing of 36equally spaced holes on the trigger pin housing mounting flange onsynchronizer housing, I5, the positioninggof'the trigger pi-n housingmay-be .made to conform to within l degrees of any desired position,greatly facilitating the installation of the flexible trigger cable,which, like the impulse cable is carried within a flexible tube.

Figure 3, -a top View, partially in section, shows the disposition ofthe rack teeth l0 on cam follower and primary impulse motor shaft 9, thekeyway i3, the channel IE, making clear the ability to orient triggerpin housing I6, and contained trigger pin 28, about cam follower andprimary impulse motor S as a trunnion. By means of dotted line, theprofile of cam i, typical for a two-lobe cam, is shown.

Figure 4 shows the use of a bell-crank in place of a pinion gear. In thefigure in question, a slot 29 is formed in cam follower and primaryimpulse motor shaft 9, the sides. of which slot may conform in contourwith a gear tooth, and coacting with which is the formed end 3B, whichmay similarly be a gear tooth in form, of bell crank 3l free tooscillate on stud iS, the other end 32 of the bell-crank, subject to thesame treatment as end Sil co-acting in slot SLi-this, too, subject tothe same treatment as. slot 29--in secondary impulse motor shaft ZI. Theoperation of the synchronizer, of course, remains the same. The use of apinion gear offers one advantage over the bell-crank construction, inthat the pinion gear may be removed and then put back in. a new positionpresenting unworn teeth, since only a fraction of the teeth are inengagement with those of the racks.

Figure 5, a detail of a section, on line 5 5 in Figure l, is more orless self-explanatory. Cam 4 is shown with respect to cam follower andlprimary impulse motor 9, slidable in a bore in housing I5, pinion gearl?, pinion gear bearing bushing i3, and pinion gear stud i9, and meansfor holding the pinion in its place, in synchronizer housing, at one endwasher S8 retained by nut 39 by means of threading 3l on stud i9, and atthe other, threading dil on stud i9 and nut eil, sho-wn in Figure 1.Secondary impulse motor 2l slidable in a bore in synchronizer I 5 isshown in relation to pinion gear I1.

Figure 6, a detail in section 011,6-5 in Figure 1, shows one method ofusing a common key to maintain a definite relationship between vthreeunits. In Figure 6, key I4, definitely located in position in a properlylocated transverse bore in synchronizer housing I5, co-acts with thekeyway I3, formed in cam follower and primary impulse motor shaft S, andkeyway 23, formed in secondary impulse motor` shaft 2|. 'Ihis keyinsures the maintenance of the proper pitch line relationship betweenrack teeth it on cam follower and primary impulse motor shaft 9, piniongear II, and rack teeth 20, on secondary im- CII Ypulse motor shaft 2l.It is not to be understood that I confine myself to this type of key andkeyway construction. The keyways may be disposed wherever convenient,and the keys similarly. However the construction shown calls for the useof but one piece and that negligible in weight. Key i4 is heldlaterally, and against any tendency to rotate by means of a nut, notshown, on threaded end 35 of key i4.

Figure 7 is a diagrammatic view of the wellknown static radial type ofaircraft engine. The disposition relative thereto of my synchronizingmechanism is shown when the gun synchronizer drive shaft is, withrespect to the crank-case E, in more or less a vertical position. In thedrawings, the impulse cable 42, is cooperative with secondary impulsemotor shaft 2l, not shown. Trigger pin cable 43, similarly iscooperative with trigger pin 28 not shown.

In Figure 8 which is a side elevation of Figure 7, is shown trigger pinhousing IG, oriented to meet a certain hypothetical condition.

Figure 9 is a diagrammatic view of the rear of the well-known staticradial type of aircraft engine, similar to that shown in Figures 7 and8, except that in this case the gun synchronizer drive shaft is disposedmore or less horizontally with respect to the engine crank-case 5. Inthis case the desired angularity, though not always, may be attained bythe orientation of the synchronizer about its base, and attaching to themounting flange on engine crank-case 6 provision for such orientationbeing made in somewhat similar fashion to that utilized for the samepurpose in the case of trigger pin housing i6 with respect tosynchronizer body l5 on the hypothetical case in point, impulse cable 42is cooperative with cam follower and primary impulse motor shaft Q, notshown.

In Figure l0, which is a side view of Figure 9, the view of thesynchronizer unit is a top view, and the method followed in attaining adesired angularity of take-off will be clearly understood. In thisfigure impulse cable 42 and trigger pin cable 43 are shown.

As has been previously mentioned, the usual procedure hitherto followedin bringing propeller and machine gun into synchrony has been one oftrial and error. This is more or less a timeconsuming operation, and toeliminate that I show in Figure l1 an application of the mechanicalcombination of worm and wheel. In the figure in question, the shaft, anintegral part of which is cam 4 shows a worm wheel formed thereon. Cam4, which hitherto has been, in effect, a part of the engine assembly,being attached to the engine gun synchronizer drive shaft, is here shownas an integral part of the synchronizer. proper, splines, dogs, or othermeans of positive drive at the outer or lower end of aforesaid shaftmating with a similarly disposed end of cam carrier sleeve 46, correctaxial `and radial placement of the latter being easily attained, andhere shown accomplished by means f of sleeve 46, which is rotatable onanti-friction bearings within cam carrier sleeve 46, the lower end ofwhich is connected to the engine shaft. suitably jcurnalled in sleeve 46is worm 45. Worm 45 meshes with worm wheel 44. It will be appreciatedthat if worm 45 is turned, worm wheel 44, an integral part of cam 4,must revolve, albeit, only minutely in travel relative to worm 45 and insleeve 45. The ratio between worm and Worm wheel is a matter of choice.Means are provided for manual turning of the worm gun synchronizer driveshaft, and, in turn, worm 45 becomes a key, connecting the drivingsleeve 45 and cam 4.

Figure 12 shows the substitution of a roller or pulley and exibleconnectorssuch as clock spring steel, as the intermediary between thecam follower and primary impulse motor shaft and the secondary impulsemotor shaft. In the drawings, primary impulse motor shaft 9 is attachedto pulley or roller 49 turning on stud 50 by means of flexibleconnectors 41 and 43. Roller 49 is in turn connected with secondaryimpulse motor 2| by means of straps 5| and 52. It should be noted thatthe disposition of the straps, compels absolute response of secondaryimpulse motor shaft 2l to the primary 9. Of course, a single strapwrapped around roller 49 would function in precisely the same fashion.It should be observed that secondary motor shaft 2i could be disposed,if desired, otherwise than in the same plane as cam follower and primaryimpulse motor shaft 9. In order words, roller or pulley 49 could be acylinder with straps 4l and 48 attached thereto at one end and straps 5Eand 52 at the other.

Figures 13 and 14 show one method of attaining some latitude in thechoice of the degree of angularity of the secondary impulse motor. Inthe detail shown in Figure 13 a section on line E3i3 of Figure 14,synchronizer housing I5 ceases to house secondary impulse motor shaft 2l. The impulse motor shaft in question, reciprocates in a bore for thepurpose in swivel housing 54 which may rotate, or swivel on sleeve 53which in turn is located and locked in place by means of nut 58. Pinionil meshes with the two impulse motor shafts 9 and 2l and oscillates onsleeve 53. These two shafts in Figures 13 and 14 are shown as square inshape. Figure 14, a sectional detail on line ifi-I4 of Figure 13, isself-explanatory.

Figure l5 shows one method for locking swivel housing 54 at the desiredangularity. A slot 51 formed in synchronizer housing l5 and a lock screw58 as illustrated, serve the purpose indicated.

In Figure 16 is shown one detail of a construction utilizing theprinciple of the ball-joint for the purpose of attaining approximatelyuniversal angular adjustment within a hemispherical field for thesecondary impulse motor shaft. Referring to the drawings, in lieu of apinion gear, I show a bell-crank 3l a right-angled one, in this caseco-acting with the primary impulse motor shaft 9 and an intermediateshaft 59. Attached to one end of said shaft 5S is a fiexible connector6I, a strap in this case by means of a swivel B. Strap 6| is attached tosecondary impulse motor shaft 64 free to reciprocate in ballendedhousing 65. Ball-ended housing E55 may be swiveled in a vertical planein any position to the vertical, from the horizontal to the Vertical,the ball end of being retained in ball socket housing S6. Ball sockethousing, 5B, may be oriented in a horizontal plane about the matingflange on synchronizer housing I5. It will be noted that strap, 5I, runsover roller, G2, turning on pin, 53. This pin and roller assembly is sodiposed as to assure minimum of change in relationship betweenball-jointed housing, 55, and secondary impulse motor shaft 65. t will,o-f course, be evident that strap 6I could be directly-connected withbell-crank end 32 by introducing means for swivelling at this point.

I have hitherto mentioned rthe, problem `cf compensating for the lag inthe firing pin mechanism, the train, so to speak, between the firing pinof the machine gun, and the actuating cam. The signincance of all this-is that the cam follow-er does not follow the cam closely enough. It isimpracticable to utilize heavier springs Vin the firing pin system;therefore, attacking the problem from the other end, the answer is toadvance the cam sufc'ien'tly to compensate for lag in the cam actuatedmechanism. One way to accomplish this is shown 'in AFigure 17.

I here use a worm and worm wheel, advancing the cam by tur-ning the wormwheel, an integral part of the cam. In'the drawing, worm 45 'meshingwith worm wheel lill has a splined end, fitting on which is a-rm ST,terminating in a ball-roller 68 normally clear of either side of channel59 formed in cylindrical sleeve lil, which is a sliding fit in aboreprepared for it in synchronizer housing I5. By means of stud ,'IIreaching the exterior of synchronizer housing I5 through opening I5bi,sleeve 'I5 may be moved axially in synchronizer housing I5, thistranslation in turn brings one side of the channel 69 into contact withroller 58, this resulting in an angular movement of arm Si and the Worm5 to which attached. The rotation of the Worm 45 functioning with wormwheel lill revolves cam li, the amount of advancement being a functionof the axial movement of sleeve l0, the length of arm 67, and theproportions of worm and worm wheel. Pin 'II may be connected with acontrol in the plane cock-pit for manual operation, the pilot advancingthe cam prior to going into a powerdive in which it is intended to bringthe machine gun or guns into play. Or a device utilizing centrifugalforce, such as the well-known centrifugal governor may be employed, theforce created being a function of the engine speed, and so arranged asnot to function until the engine speed exceeds some predetermined R.'P.M. In a case Where the synchronizer is interconnected with a mechanisminsuring an automatic advance it may sometimes be necessary to return`sleeve 'I to normal position when a power dive is ended and for thispurpose spring 'I2 is shown.

In Figure 18 a fragmentary detail shows means for advancing,automatically, the cam to meet the abnormal conditions existing during apowerdive as it effects gun synchronization. In the case shown,centrifugal force supplies the power required to advance the cam, and asan integral part of the synchronizer unit itself. I show the sameelementsdisclosed in Figure 17 with the exception of an exteriorlyprojecting pin 1I, to wit, worm 45 meshing with Worm wheel 44, notshown, arm 61, ball roller 68, channel 69 in cylin.- drical sleeve 'IILI may here add that the screw driver slot shown at the end of worm 45,is for the purpose of turning the Worm to bring the cam to the correctposition with respect to the engine gun synchronizer drive shaft at thetime of the original installation. It will be understood that .arm 61has been removed during this operation. Again considering the drawings,I show a bowl-shaped governor body I5 retained as an integral part ofsleeve it, for purposes of illustration, I show this accomplished bymeans of locknut 16. Governor body 'I5 has formed in it a number ofradial channels 'I4 in each one of which reposes a ball 73. These ballsI3 are retained in place by the bowl-shaped nature of the governor bodyand the outside of one of the flanges which with the other, ofcylindrical sleeve 'Ill forms channel 59. As sleeve llt, which may beconsidered for all practical purposes a part of the engine gunsynchronizer drive shaft, turns,

the centrifugal force created will cause all balls to move out radially,and the centrifugal force produced, bearing in mind that the latter is afunction of the square of the velocity, attains considerableproportions. This force I make do useful work, and due to the contour ofthe ball track in the governor body, this centrifugal force is resolvedinto two components, one of these advantage residing in a worm andvworm-wheel combination is great enough to warrant entire disregard ofthe force exerted by the cam following mechanism on the cam itself, asalso being necessary to overcome. In view of the irreversible nature ofthe same combination spring 'E22 return cylindrical sleeve 'It to normaloperating position when the engine is` again operating at ordinary R. P.Ms. This, of course, by virtue of the same procedure, but in reverseorder, returns the cam to itsy original and ordinary operating position.

In Figure 19 is shown another method of advancing the cam. This View,while only a detailed section, shows the essential feature involved.I-Iere I produce the desired advance either manually or automatically byhydraulic force. In this case I, in effect, make the cam a hydraulicpiston controlling the piston action of the cam by means of a slot and apin. Referring to the drawings, the essential parts of the synchronizerare shown, cam Il, roller l, cam follower and impulse motor shaft 9,synchroniser housing I5, and anti-friction bearings for carrying bothradial and thrust load. In addition is shown cylinder sleeve '19, whichfor purposes of explanation may be considered an extension of the enginegun synchronizer drive shaft. This is maintained in correct position insynchronizer body I5, by means of the anti-friction bearings mentioned,and distance sleeve 84. In cylinder sleeve I9 is cylinder chamber 8D,into which is tted, as if a piston, the shaft of cam il. Cut into thecylindrical surface of said shaft of cam 'i is an elongated slot "Il,shown clearly in Figures 20 and Z1. Coi-acting with this slot TI is pin38, retained in cylindrical sleeve 79. In normal operation, one end ofslot 'I1 is retained against pin 'I9 by the pressure exerted on the faceof cam 4 by vroller 'I by virtue of the work being exacted from thesynchronizer. However, hydraulic pressure may alter this relationship ofslot and pin. Hydraulic chamber is by means of passage- Way throughdistance-sleeve 8d and passage- Way 91 in synchronizer housing I5 placedinto communication with external means for producing a desired hydraulicpressure. This may be in connection with the regular oiling system ofthe engine, provision being made to utilize the much higher pressuresexisting when an engine is turning at an abnormally high speed. It maybe a separate oil pump, functioning similarly. It may also behydraulically connected with the cockpit, the equivalent of a hydraulicram permitting the pilot, manually, to advance the cam prior to enteringa power-dive when the gun is to be brought into play. In any of thesecases due to the nature of the slot, when hydraulic pressure sufficientto overcome the load on cam 4 is effected in cylinder sleeve chamber 80cam 4 uwill be forced outward, but itsV outward movement is controlledby pin 18 acting in slot 11. Due to the nature of the latter as cam 4 isforced outwardly, it must turn as well, in response to the controlcited. The limit of outward movement and of advance is, of course,determined by the relationship that has been previously established. Thedesign of cam follower and impulse motor shaft 9, as well .as roller 1,must make provision for any outward movement of cam 4 that may occur. Noprovision need here be made to return cam 4 to normaloperating positionsince the working load on cam 4 itself will return the latter to thatplace the instant the hydraulic pressure in chamber 80 is released.

Figures 20 and 21 show the relation of slot 11 and pin 18 the former innormal position, the latter in advanced operating condition,

In Figure 22, I show still another method of effecting automatic advanceof a cam, the means therefor being an integral part of the synchronizermechanism. I here utilize centrifugal force as the actuating power witha governor-like type of mechanism such as disclosed in Figure 18.

However, I employ the centrifugal force, created when the abnormaloperating conditions hitherto discussed, exist, in effecting an axialdisplacement of the cam, by virtue of which lateral displacement arotary displacement is impressed on said cam. The degree of suchrotation is a measure of the advance desired.

In the drawings, the components are as hitherto discussed, except thatinstead of a cylindrical sleeve 10 a thrust plate 90 becomes thelaterally moving element in the centrifugal` unit. Thrust plate 90 byvirtue of crosspiece 89 may be considered with cam 4 as a unitarystructure` being attached thereto through openings in camcarrying sleeve19 which., as heretofore stated, may be simply considered as anextension of the engine gun synchronizer drive shaft.

As the centrifugal force created by the rotation of the ball train 19attains a magnitude greater than the load being carried by cam` 4, asdetermined by calculation, the lateral movement of thrust plate 90, inresponse thereto, necessarily will result in a lateral displacement ofsaid cam l such lateral displacement having a rotary component by virtueof the limitation introduced in the employment of a pin 18 xed incam-carrying sleeve 19 and co-acting in slot 11 formed in cam 4. Therelationship of pin and slot is established to attain the desiredadvance. Provision must necessarily be made in relationship of cam,roller and cam follower for the axial, or lateral, displacement of therst mentioned.

Figure 23 shows still another means for attaining automatic advance. Themethod disclosed is very similar to that shown in Figure 22, except thatthe necessity of providing in the mechanism for any axial or lateralmovement of the cam is eliminated. The elements involved are preciselysimilar except by the interposition of an intermediate floating sleeve Iaccomplish the last mentioned object.

In the drawing, thrustplate 90 with exactly the same function ashitherto described, supports pins 93. These pins 93 extend inwardlythrough openings in cam-carrier sleeve 19 terminating in slots 94 inintermediate sleeve 92. Sleeve 92, in effect, is an integral part `ofcam 4. It is shown locked into position between a shoulder and nut. Theslots 94 in question could be formed in the cam 4 shaft as shown inFigure 19. This merely shows one of a variety of ways and sleeve 92 as aunitary structure, from the axial or lateral displacement ofthrust-plate 90 it immediately follows that the translation of theposition of pins 93 may only be accomplished by effecting a change inthe relationship of said pins 93 to slots 94 in sleeve 92.

By design, the lateral movement of pins 93 may be converted into turningeffort, and so it is that cam 4 must rotate with respect to cam-carriersleeve 19 in the amount specified to attain the desired result.

Figure 24 is a detail showing sleeve 92, pin 93, and slot 94.

As I have previously mentioned, anything that may shorten the length oftime consumed in effecting synchrony between propeller and machine gunis an important desideratum. In Figure 11, I have shown a constructionthat accomplishes this, a construction having universal latitude, inthis case, 360 degrees, in the proper relationship between the gunsynchronizer drive shaft and the impulse motor shaft, effecting thiswithout necessity of removing the synchronizer unit from its position onthe engine. In those cases where an adjustment through a 360 degreerange is not necessary, but on the other hand only a limited latitude inadjustment, predicted on an approximately correct installation in thefirst instance, I offer a simple solution:

In Figure 25 I show one construction in which spiral splines areutilized to attain a considerable amount of latitude inafter-installation adjustment. The latitude offered is, of course, afunction of the amount of lead possessed by the said spiral splines.

Referring to the drawings, cam 4 is shown, having formed thereon spiralsplines 91; mating with spiral splines 91 is splined sleeve 98, the boreof which mates with said spiral splines 91, and on the outer cylindricalsurface of which are formed screw threads. Mating with the screw threadson splined sleeve 98 are screw threads in the bore of adjustment collar99. Adjusting collar 99, while free to be turned in camcarrier 96, is bydesign restrained from all lateral movement with respect to said camcarrier 9S. Conveniently disposed in the periphery of adjusting collar99 are Spanner holes 99a by which through slots |03 in cam-carrier 96,said adjusting collar 99 may be turned. Access to slots |03 incam-carrier 90 may be gained by means of openings |50 through the wallsof synchronizer housing l5, the location of such an opening being shownwith plug closure in place. I may point out the dogs |00 on splinedsleeve 98 interlocking with dogs on dog-carrier |02. The sequence ofevents in making an adjustment is as follows: It is assumed that thesynchronizer,

Yof construction.r Therefore, considering cam 4 at the time ofinstallation,I is roughly correctly synchronized, a matter of but a fewdegrees out of synchrony. Access is had to adjusting co-llar 99 in thefashion above indicated. Adjusting collar S3 is turned. The rotation ofthis, in view of its own retention against lateral movement may resultonly in an effort to carry splined sleeve 38 with it. However, in viewof the irnp-ossibility of rotation of the latter, springing from theinterlocking of dogs i90 with dogs ll splined sleeve Q8 may only movelaterally, provision for such movement being made in the design ofcam-carrier 96. It will be appreciated that the movement of splinedsleeve 98 will change the relative interlocking position of the dogs. Assplined sleeve 93 moves laterally with respect to splines Q'l on cam fl,the latterY being, by design, prevented from axial or lateral movement,in this case with respect to cam-carrier @ii-and for illustration shownaccomplished by pin S5 splines @l must respond by following the matingsplines in splined sleeve 98. In so doing cam 4i is turned, and insomuchas cam 4 is turned, is the phase relation between gun synchronizer driveshaft and synchronizer impulse motor shafts changed. The relationshipbetween propeller position and the time of gun fire may be quicklychecked, and further correction, if necessary, made. The time-savinginvolved will be understood, since no longer is it necessary toremove... the unit to change the cam setting. From time to time or asrequired, adjustment to compensate for wear may be made in adjusting thecam position, this being a matter of minutes only, if not seconds, asthe synchronizer proper, impulse cable, trigger pin cable, etc., areno-t disturbed.

While `I have previously shown constructions permitting rapid adjustmentof the cam to effect the desired synohrony, in many cases the use of auniversally or partially adjustable cam arrangement is not feasible, andfor those cases I v show a method eliminating in large measure thetrial-and-error procedure hitherto practised in attaining the desiredend. In Figure 27 I show, diagrammatically, the'train existing betweenpropeller and the engine gun synchronizer drive the latter terminatingin a splined end. I indicate the train by a series of pulleys, and abelt. Describing the drawings, the propeller blades ll and lill areconnected in the manner indicated by means of pulley l l l, belt I l0,pulleys i2 and l i3 with pulley l l-'l driving gun synchronizer driveshaft i terminating in splines 2. Machine gun muzzle lfd is shown at anangle with the center line of the propeller, the latter placed in avertical position, center line H09 passing through the line of gun-lire.The propeller is to be understood as turning clockwise, and passes, ofcourse, through the line of re. With the propeller placed verticallywith respect to the designed horizontal axis of the engine, an indexline in this case, O O, is placed in a convenient position on gunsynchronizer drive shaft-for example; this may be scribed on oneparticular spline, This index may be placed in some deiinite relation toa stationary index, scribed for instance, on the crank-case gunsynchronizer mounting flange, or an index on the latter may be placedthereon in register with that en the spline. If, now, a circular dial H5properly marked, in degrees, with a central clearance hole ill' anddowel pin holes H6 is placed on the engine crank-case gun synchronizermounting flange, dowels in the latter locating said dial H5 by virtue ofthe dowel pin holes HG the dial H5 we have established a very definitemeans for placing the cam correctly, and on the rst essay. If nowpointer H8 with splines H9 mating with those on gun synchronizer driveshaft 2 with the pointer coinciding with the zero line cn dial i l5 isslipped over splines 2 and the propeller is turned clockwise until thecenter-line of blade H31, in this case, is pierced by the line of fire,pointer H8 will move over the face of dial liti. It follows that theangularity between the vertical and the new gun re intercepting positionof the propeller may be immediately read on dial l i5. To illustrate,let us assume the pointer hadl moved from zero setting to 132 degrees.Again, for purposes of illustration assume that experience has, for thisparticular installation, disclosed that the synchronizer should preventall gun fire from a point 25 degrees in advance of the arrival of thepropellerV blade in front of the particular machine gun muzzle |08, thisallowing for lag, and other extraneous influences. If, therefore, thepropeller be turned counterclockwise until 25 degrees has beensubtracted from l32 degrees, that is untilthe pointer H8 coincides with107 degrees on dial H5 the propeller is now in the position at which thegun must not fire. If the cam d is now mounted on gun synchronizer driveshaft in such position as to retract impulse motor shaft 9 to themaximum, that is, if the cam is placed with its major axis coincident indirection with the axis of the cam follower7 proper synchrony will behad.

I have hitherto discussed constructions utilizing, primarily impulsemotor shaftsk functioning 9' at right angles, or, angularly, directlyabove the source of power-supply and converting at the same time rotaryinto reciprocating motion. However, as previously recited, an occasionalinstallation requires a synchronizer in which the reciprocating powersupply must be offsetV or staggered with respect to the original sourceof rotary motion. AI show, in Figures 30, 31 and 32 how I do this,retaining the vital features of simplicity, minimum wear, minimumweight, etc., while at the same time the construction shown, lendsitself, as will be perceived, particularly well to orientation of theimpulse motor shaft. In Fgurel, I show a combination in one synchronizerunit of several of the features more particularly, and singly, discussedpreviously, although it had, hitherto, been entirely obvious that anydesired combination of functions, or a combination of all functionscould be incorporated into and become an integral part of thesynchronizer unit. Figure 33 is an enlarged detail showing a combinationof the various elements combined in the structure shown in Figures 30,3l and 32, the latter, Figure 32, being a top view of the structureshown in Figure 30.

Describing now the drawings in Figure 30, I show a partial section on33-35) of the structure shown in Figure 32. My main elements remain ashitherto. I show cam 4 operating in conjunction with roller 'l and whathas hitherto been cam follower and primary impulse motor shaft 9 becomessimply a cam follower, the need for more than one impulse motor shaftdisappears, the secondary impulse motor shaft acquiring a more or lessuniversal function. The same gear train, rack, pinion and rack areutilized,l but in somewhat different fashion. Pinion il oscillatingabout pinion gear stud I9 in this case has a companion gear Ila, shownin Figure 31, integral therewith, this integration Cil being effected byany of the well-known mechanical means, as here shown the pinions beinga unit, being joined by a sleeve. The mechanism for retention shownfollows the practice revealed in Figure 5. C'o-acting with pinion gearila, is impulse motor shaft 2i which in this case reciprocates inimpulse motor shaft housing |20, the latter being attached tosynchronizer housing l5 by mating flanges rigidly held together by meansof machine screws or other mechanical means. It will readily be observedthat, by design, impulse motor shaft 2l may be oriented about piniongear stud i9 central thereto, as well as to the gear containing recessin synchroniser housing i5, To attain the degree of latitude inadjustment, in orienting impulse motor housing B2B a series of threadedholes H22 may be formed in the synchronizer housing harige mating withthat on the impulse motor shaft housing i 2U. The practice may well bethat shown in Figure 2.

To attain still greater refinement in placement, the recited flange onimpulse motor shaft housing S20 may have the machine screw, or boltholes elongated as shown in detail in Figure l5. In Figure 30 I alsoshow another construction increasing still further the more or lessuniversal adaptability of my invention. I show cover housing 62Ereplacing the more conventional arrangement shown in Figures l, 2 and 3,this cover housing i2! having a flange corresponding to the flange ontrigger pin housing iii and similarly on synchronizer housing l5 amating ange identical to that with which the trigger pin housing itmates. The signicance of this is that for convenience of installation,cover housing iZl and the trigger pin housing it may be interchanged endfor end. The only difference in operation when so reversed is that toarrest the operation of the machine gun, the trigger pin 2t instead ofpulling roller 1 from the rolling surface of cam d will, in effect, pushit out of contact, by virtue of the design of the engaging end of thetrigger pin. It will be observed that any reasonable offset or staggermotor shaft 2l with respect to cam follower 9 is attainable. For sake ofclearness, keys and keyways are not shown.

Referring to Figure 33 which is an enlarged detail of the drive betweenengine gun synchroizer drive shaft l the cam follower 9 shown in Figure3l, on section l-Iii of Figure 30, governor bowl l5 for purposes ofillustration, has formed in its lower end a splined recess mating withsplines on the end of the shaft mentioned. Centrifugal force is hereharnessed in precisely the same way as is set forth in the descriptionof Figure 23. However, instead of direct actuation of cam l ashereinbefore recited, the actuation in this case is directly to the camcarrier, "i9 and not as in the former case to sleeve 92 nor directly tothe shaft of cam 4l. The function of cam carrier i9 in Figure 23becomes, in effect, the same as driving sleeve 96a in Figure 25. Theconstruction, in train, toward the cam, parallels the construction shownin Figure 25 and other explanation would not seemgnecessary` While Ihave illustrated and described my invention with some degree ofparticularity, I realize that in practice, various alterations andmodications therein may be made. I therefore reserve the right andprivilege of changing the form of the details of construction, orotherwise altering any arrangement of parts without departing from thespirit of the invention or the scope of the claims that follow.

It will be apparent that any form of the synchroniser shown herein maybe utlized in the operation of two machine guns simultaneously, the onlyrequirement being that impulse cables be connected to the two impulseshafts and to the two machine guns, with the guns properly orientedrelative to the propeller.

Having thus described my invention, what I claim as new and desire toprotect by United States Letters Patent, is:

I claim:

1. In a gun synchroniser for attachment to an engine, a casing, areciprocable member therein, a second reciprocable member in said casingoperatively connected to the rst member for reciprocation therewith,said second member being arranged at an angle to the first member, meansattache-ble to either member to connect it to an operating part of thegun, said means being actuated by said operating part of the gun to movesaid member in one direction, cam means to move the member in theopposite direction, and means to render the first-named meansineffective at will, the relative angularity of said members being suchthat one thereof is accessible for connection to an operating part ofthe gun when engine construction renders the other member inaccessiblefor such connection.

2. In a gun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to the rst member for reciprocationtherewith, said second member being disposed in angular relation to therst member and being connected to the first member by a rack-andpinion,means attachable to either member to connect it to an operating part ofthe gun, said means being actuated by said operating part of the gun inone direction, cam means to move the' member in the opposite direction,and means to render the first-named means ineffective at will.

3. In a gun synchroniser, a reciprocable member, a second reciprocablemember operatively connected to the first member for reciprocationtherewith, said second member being arranged at an angle to the firstmember, means attachable to either member to connect it to an operatingpart of the gun, said means being actuated by said operating part of thegun to move said member in one direction, cam means to move the memberin the opposite direction, and means to render the first-named meansineffective at will comprising a pin normally biased to seat in achannel formed transversely in one of said members.

4. In a gun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to the rst member for reciprocationtherewith, said second member being arranged at an angle to the firstmember, means attachable to either member to connect it to an operatingpart of the gun, said means being actuated by said operating part of thegun to move said member in one direction, cam means to move the memberin the opposiate direction, means to render the iirst-named meansineffective at will comprising a pin normally biased to seat in achannel formed transversely in one 0f said members, and a housing havinga guideway therein for said pin, said housing being adjustable about theline of reciprocation of said channeled member.

5. In a gun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to the rst member for reciprocationtherewith, said second member being arranged at an angle -to the nrs-tmember, said members' being keyed together for relative movement in acommon plane, means attachable to either member to connect it to anoperating part of the gun, said means being actuated by said operatingpart of the gun to move said memberin one direction, cam means to movethe member in the opposite direction, and means to render thefirst-named means ineiective at will.

6. In a gun synchonizer, a casing therefor, a reciprocable membermounted in said casing, engine driven cam means for moving saidrecipiiccable member in one direction, means connecting said member toan operating part of the gun and operated by the operating part of thegun to move said member in'the opposite direction to cause it to yfollowsaid cam, a locking member housing secured to said casing and providedwith a guideway, a locking member movable in said guideway to engagesaid reciprocable member to lock it against reciprocation, said housingbeing adjustable about the line of reciprocation of said reciprocablemember.

7. In a gun synchronizer, a casing therefor, a reciprocable membermounted in said casing, a second reciprocable member mounted in saidcasing Aand operatively connected to the rst memberfor reciprocationtherewith, engine driven cam means for moving one of saidrecprocable'members in one direction, means connecting one of saidmembers to an operating part of the gun and operated by the actuatingpart of the gun to move said member in the opposite direction, a lockingmember housing secured to said casing and provided with a guideway, alocking member movable in said guideway to engage one of saidreciprocable members to lock it against reciprocation, said housingbeing adjustable about the line of reciprocation of said reciprocablemember.

8. In a gun synchronizer, a casing therefore, a reciprocable membermounted in said casing, engine driven cam means for moving saidreciprocable member in one direction, means connecting said member to anoperating part of the gun and operated by the actuating part of the gunto move said member in the opposite direction to cause it to follow saidcam, said member being provided with an annular formation, a

locking member housing secured to said casing and provided with aguideway, a locking member movable in said guideway to engage theannular formation of said reciprocable member to lock it againstreciprocation, said housing being adjustable about the line ofreciprocation of said reciprocable member.

9. In a gun synchronizer, a1 casing therefor, a reciprocable membermounted in said casing, a second reciprocable member mounted in saidcasing and operatively connected to the iirst member for reciprocationtherewith, engine driven cam means for moving said reciprocable memberin one direction, means connecting one of said members to an operatingpart of the gun and operated by the actuating part of the gun to movesaid member in the opposite direction, one of said members beingprovided with an annular formation, a locking member housing secured tosaid casing and provided with a guideway, a locking member movable insaid guidewayy to engage said annular formation to lock said membersagainst reciprocation, said housing being adjustable about the line ofreciprocation of the reciprocable member having the annular forma- 10.VIn a rgun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to said rst member for reciprocationtherewith, said second member being disposed in angular relation to therst member and being connected to the first member by a rack and pinion,means attachable to said members to connect them to operating parts ofguns, said means being ractuated by said operating parts of the guns tomove said members in one direction, cam means associated with one ofsaid members to move the members in the opposite direction, and means torender the first named means ineiective at will. i

11. In a gun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to the first member for reciprocationtherewith, said second member being arranged at an angle to the firstmember, means attachable to said members to connect them to operatingparts of guns, said means being actuated by said operating parts of theguns to movesaid members in one direction, cam means associated with oneof said members to move the members in the opposite direction, and meansto render the'rst named means ineiectiveat will comprising a pinnormally biased to seat in a channel formed transversely in one of saidmembers.

12. In a gun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to the rst member for reciprocationtherewith, said second member being arranged at an angle to the rstmember, said members being connected together for relative movement in acommon plane, means attachable to said members to connect them tooperating parts of guns, said means being actuated by said operatingparts of .the guns to move said members in one direction, cam meansassociated with one of said members to move the members in the oppositedirection and means to render the first named means ineffective at will.

13. In a gun synchronizer, a reciprocable member, a second reciprocablemember operatively connected to the first member for reciprocationtherewith, separate' means attachable to said members to connect themrespectively to operating parts of separate guns, said means beingactuated by said operating parts of the guns to move said members in onedirection, cam means associated with one of said members to move themembers in the opposite direction, and means to render the first namedmeans ineffective at will.

14. In a gun synchronizer, a reciprocable member, a second reciprocablemember, means connecting said reciprocable members whereby the membersare simultaneously reciprocated, said second member being adjustablerelative to the iirst whereby the angle of reciprocation of the secondmember relative to the first member can be varied, means attachable toeither of said members to connect it to an operating part of the gun,said means being actuated by said operating part of the gun to move saidmember in one direction, cam means associated with one of said membersfor moving said members in the opposite direction, and'means for lockingsaid members against reciprocation at will,

15. In a gun synchronzer, a reciprocable member, a second reciprocablemember, means connecting said reciprocable members whereby the membersare simultaneously reciprocated, said second member being adjustablerelative to the first whereby the angle of reciprocation of the secondmember relative to the rst member can be varied, means attachable tosaid members to connect them to operating parts of guns, said meansbeing actuated by said operating parts of the guns to move said membersin one direction, cam means associated with one of said members formoving said members in the opposite direction, and means for lockingsaid members against reciprocation at will.

16. In a gun synchronizer, a reciprocable member, a second reciprocablemember, meansI connecting said reciprocable members whereby the membersare simultaneously reciprocated, said second member being adjustablerelative to the rst whereby the angle of reciprocation of the secondmember'relative to theV iirst member can be varied, means attachable tceither of said members to connect it to an operating part oi the gun,said means being actuated by said operating part of the gun to move saidmember in one direction, cam means associated with one of said membersfor moving said members in the opposite direction, a housing having aguideway therein, and a locking member movable in said guideway toengage one of said members to lock said members against reciprocation,said' housing being adjustable about the line of reciprocation of themember engaged by the locking member.

17. In a gun synchronizer, a reciprocable member, a second reciprocablemember, means ccnnecting said reciprocable members whereby the membersare simultaneously reciprocated, said second member being adjustablerelative to the iirst whereby the angle of reciprocation of the secondmember relative to the rst member can be varied, means attachable tosaid members to connect them to operating parts of guns, said meansbeing actuated by said operating parts oi the guns to move said membersin one direction, cam means associated with one of said members formoving said members in the opposite direction, a housing having aguideway therein, and a locking member movable in said guideway toengage one of said members to lock said members against reciprocation,said housing being adjustable about the line of reciprocation of themember engaged by the locking member,

18. In a gun synchronizer for attachment to an engine, a casing, areciprocable member therein, a second reciprocable member in said casingoperatively connected to the first member for reciprocation therewith,said second member being arranged at an angle to the first member, meansattachable to either member to connect it to an operating part of thegun, said means being actuated by said operating part of the gun to movesaid member in one direction, cam means driven by said engine to movethe member in the opposite direction, means to render the first-namedmeans ineffective at will, the relative angularity of said members beingsuch that one thereof is accessible for connection to an operating partof the gun when engine construction renders the other memberinaccessible for such connection, and means for varying the relationbetween the cam and the engine to compensate for variation in lag in thetrain of mechanism caused by variations in engine speed.

19. In a gun synchronizer for attachment to an engine, a casing, areciprocable member therein, a second reciprocable member in said casingoperatively connected to the first member for reciprocation therewith,said second member being arranged at an angle to the rst member, meansattachable to either member to connect it to an operating part of thegun, said means being actuated by said operating part of the gun to movesaid member in one direction, cam means driven by said engine to movethe member in the opposite direction, means to render the rstnamed meansineiective at will, the relative an- -gularity of said members beingsuch that one thereof is accessible for connection to on operating partof the gun when engine construction renders the other memberinaccessible for such connection, and manually operable means forvarying the relation between the cam and the engine to compensate forvariation in lag intheV train of mechanism caused by variations inengine speed.

20. In a gun synchronizer for attachment to an engine, a casing, areciprocable member therein, a second reciprocable member in said casingoperatively connected to the first member for reciprocation therewithysaid second member being arranged at an angle to the rst member, meansattachable to either member to connect it to an operating part of thegun, said means being actuated by said operating part` of the gun tomove said member in one direction, cam means driven by said engine tomove the member in the opposite direction, means to render thefirst-named means ineffective at will, the relative angularity of saidmembers being such that one thereof is accessible for connection to anoperating part of the gun when engine construction renders the othermember inaccessible for such connection, and automatically operatingmeans for varying the relation between the cam and the engine tocompensate for variation in lag in the train of mechanism caused byvariations in engine speed.

21. In a gun synchronizer for attachment to an engine, a casing, areciprocable member therein, a sleeve member rotatable in said casingand driven by said engine, a cam rotatable in said casing for movingsaid reciprocable member in one direction, said cam having a stem ttingin said sleeve, a worm gear on the end of the stem within said sleeve, aworm mounted in said sleeve and engaging said worm gear to provide adriving coupling between the sleeve and the cam stem, said worm beingrotatable to rotate said stem relative to said sleeve whereby theposition of the eccentric part of the cam relative to any given locationon said sleeve can be varied.

22. In a gun synchronizer for attachment to an engine, a casing, areciprocable member therein, a sleeve member rotatable in said casingand driven by said engine, a cam rotatable in said casing for movingsaid reciprocable member in one direction, said cam having a stemfitting in said sleeve, a worm gear on the end of the stem within saidsleeve, a worm mounted in said sleeve and engaging said worm gear toprovide a driving coupling between the sleeve and the cam stem, saidWorm being rotatable manually while the sleeve is at rest to rotate saidstem relative to said sleeve whereby the position of the eccentric partof the cam relative to any given location on said sleeve can be varied,said casing being provided with an opening for rendering said wormaccessible for rotating the same.

JAIVIES E. DIAMOND.

